#include <asn_application.h>
#include <asn_internal.h>
#include <per_decoder.h>

/*
 * Decode a "Production of a complete encoding", X.691#10.1.
 * The complete encoding contains at least one byte, and is an integral
 * multiple of 8 bytes.
 */
asn_dec_rval_t uper_decode_complete(
    const asn_codec_ctx_t* opt_codec_ctx, const asn_TYPE_descriptor_t* td,
    void** sptr, const void* buffer, size_t size) {
  asn_dec_rval_t rval;

  rval = uper_decode(opt_codec_ctx, td, sptr, buffer, size, 0, 0);
  if (rval.consumed) {
    /*
     * We've always given 8-aligned data,
     * so convert bits to integral bytes.
     */
    rval.consumed += 7;
    rval.consumed >>= 3;
  } else if (rval.code == RC_OK) {
    if (size) {
      if (((const uint8_t*) buffer)[0] == 0) {
        rval.consumed = 1; /* 1 byte */
      } else {
        ASN_DEBUG("Expecting single zeroed byte");
        rval.code = RC_FAIL;
      }
    } else {
      /* Must contain at least 8 bits. */
      rval.code = RC_WMORE;
    }
  }

  return rval;
}

asn_dec_rval_t uper_decode(
    const asn_codec_ctx_t* opt_codec_ctx, const asn_TYPE_descriptor_t* td,
    void** sptr, const void* buffer, size_t size, int skip_bits,
    int unused_bits) {
  asn_codec_ctx_t s_codec_ctx;
  asn_dec_rval_t rval;
  asn_per_data_t pd;

  if (skip_bits < 0 || skip_bits > 7 || unused_bits < 0 || unused_bits > 7 ||
      (unused_bits > 0 && !size))
    ASN__DECODE_FAILED;

  /*
   * Stack checker requires that the codec context
   * must be allocated on the stack.
   */
  if (opt_codec_ctx) {
    if (opt_codec_ctx->max_stack_size) {
      s_codec_ctx   = *opt_codec_ctx;
      opt_codec_ctx = &s_codec_ctx;
    }
  } else {
    /* If context is not given, be security-conscious anyway */
    memset(&s_codec_ctx, 0, sizeof(s_codec_ctx));
    s_codec_ctx.max_stack_size = ASN__DEFAULT_STACK_MAX;
    opt_codec_ctx              = &s_codec_ctx;
  }

  /* Fill in the position indicator */
  memset(&pd, 0, sizeof(pd));
  pd.buffer = (const uint8_t*) buffer;
  pd.nboff  = skip_bits;
  pd.nbits  = 8 * size - unused_bits; /* 8 is CHAR_BIT from <limits.h> */
  if (pd.nboff > pd.nbits) ASN__DECODE_FAILED;

  /*
   * Invoke type-specific decoder.
   */
  if (!td->op->uper_decoder) ASN__DECODE_FAILED; /* PER is not compiled in */
  rval = td->op->uper_decoder(opt_codec_ctx, td, 0, sptr, &pd);
  if (rval.code == RC_OK) {
    /* Return the number of consumed bits */
    rval.consumed =
        ((pd.buffer - (const uint8_t*) buffer) << 3) + pd.nboff - skip_bits;
    ASN_DEBUG(
        "PER decoding consumed %ld, counted %ld", (long) rval.consumed,
        (long) pd.moved);
    assert(rval.consumed == pd.moved);
  } else {
    /* PER codec is not a restartable */
    rval.consumed = 0;
  }
  return rval;
}

asn_dec_rval_t aper_decode_complete(
    const asn_codec_ctx_t* opt_codec_ctx, const asn_TYPE_descriptor_t* td,
    void** sptr, const void* buffer, size_t size) {
  asn_dec_rval_t rval;

  rval = aper_decode(opt_codec_ctx, td, sptr, buffer, size, 0, 0);
  if (rval.consumed) {
    /*
     * We've always given 8-aligned data,
     * so convert bits to integral bytes.
     */
    rval.consumed += 7;
    rval.consumed >>= 3;
  } else if (rval.code == RC_OK) {
    if (size) {
      if (((const uint8_t*) buffer)[0] == 0) {
        rval.consumed = 1; /* 1 byte */
      } else {
        ASN_DEBUG("Expecting single zeroed byte");
        rval.code = RC_FAIL;
      }
    } else {
      /* Must contain at least 8 bits. */
      rval.code = RC_WMORE;
    }
  }

  return rval;
}

asn_dec_rval_t aper_decode(
    const asn_codec_ctx_t* opt_codec_ctx, const asn_TYPE_descriptor_t* td,
    void** sptr, const void* buffer, size_t size, int skip_bits,
    int unused_bits) {
  asn_codec_ctx_t s_codec_ctx;
  asn_dec_rval_t rval;
  asn_per_data_t pd;

  if (skip_bits < 0 || skip_bits > 7 || unused_bits < 0 || unused_bits > 7 ||
      (unused_bits > 0 && !size))
    ASN__DECODE_FAILED;

  /*
   * Stack checker requires that the codec context
   * must be allocated on the stack.
   */
  if (opt_codec_ctx) {
    if (opt_codec_ctx->max_stack_size) {
      s_codec_ctx   = *opt_codec_ctx;
      opt_codec_ctx = &s_codec_ctx;
    }
  } else {
    /* If context is not given, be security-conscious anyway */
    memset(&s_codec_ctx, 0, sizeof(s_codec_ctx));
    s_codec_ctx.max_stack_size = ASN__DEFAULT_STACK_MAX;
    opt_codec_ctx              = &s_codec_ctx;
  }

  /* Fill in the position indicator */
  memset(&pd, 0, sizeof(pd));
  pd.buffer = (const uint8_t*) buffer;
  pd.nboff  = skip_bits;
  pd.nbits  = 8 * size - unused_bits; /* 8 is CHAR_BIT from <limits.h> */
  if (pd.nboff > pd.nbits) ASN__DECODE_FAILED;

  /*
   * Invoke type-specific decoder.
   */
  if (!td->op->aper_decoder) ASN__DECODE_FAILED; /* PER is not compiled in */
  rval = td->op->aper_decoder(opt_codec_ctx, td, 0, sptr, &pd);
  if (rval.code == RC_OK) {
    /* Return the number of consumed bits */
    rval.consumed =
        ((pd.buffer - (const uint8_t*) buffer) << 3) + pd.nboff - skip_bits;
    ASN_DEBUG(
        "PER decoding consumed %zu, counted %zu", rval.consumed, pd.moved);
    assert(rval.consumed == pd.moved);
  } else {
    /* PER codec is not a restartable */
    rval.consumed = 0;
  }
  return rval;
}
